Routers, switches, and firewalls join and protect out networks, but how did we end up with this interconnected network of devices?
It started way back in 1962 when Paul Baran of the RAND Corporation was commissioned by the U.S. Air Force to do a study on how to maintain control over its aircraft and nuclear weapons after a nuclear attack. This project was meant primarily to be a military network that would allow the armed forces to maintain communication with other commands throughout the United States in the event of a catastrophic event. This would allow the armed forces to maintain control of the nuclear weapons needed to launch a counterattack.
In 1968, ARPA (Advanced Research Projects Agency) awarded the ARPANET (Advanced Research Projects Agency Network) contract to BBN (Bolt, Beranek and Newman). The physical network was constructed in 1969, linking four nodes: the University of California at Los Angeles, SRI (Stanford Research Institute), the University of California at Santa Barbara, and the University of Utah. The network was wired together using only 50-kbps circuits. From there, the Internet was developed and flew into modern society, now running the backbone of every major company on the planet. In 1973, development began on the protocol later termed the Transmission Control Protocol/Internet Protocol (TCP/IP), but it was 1977 before it was demonstrated. This new protocol was created to allow diverse computer networks to interconnect and communicate with each other. Ten years later, in 1983, TCP/IP became the core Internet Protocol on ARPANET.
ARPANET was divided into two networks, MILNET and ARPANET. MILNET was to serve the needs of the military, and ARPANET was to support the advanced research component that later was to include commerce. Finally, in the early 1990s, you could now order pizza and take care of your bank account online. We've come a long way since the 1960s. In the next section we will uncover how these components work using simple explanations and analogies.